In order to maximize your fitness routine at the gym, be sure to only rest when needed between sets. This will save time, at the gym and get you moving to other activities quicker. Later on in your workout you'll need more rests, however you can start it off strong without any ill effects.
Take time to stretch in between sets of weightlifting. Research has shown that people who stretch while waiting to start their next set of lifting weights have stronger muscles than those who just sit and wait between sets. Stretching is a little thing you can do to strengthen yourself while you're resting.